A data processing system provides annotation of a document with annotations inputted through an electronic tablet, a keyboard and an audio assembly. The annotations are entered in a modeless operation of the three input streams. Input by the tablet utilizes a two ended pen. One end of the pen is used...http://www.google.de/patents/US5625833?utm_source=gb-gplus-sharePatent US5625833 - Document annotation & manipulation in a data processing system
